The 3rd Generation Partnership Project (3GPP) defines an architectural of a policy and charging control (PCC) framework. The PCC framework includes: a policy and charging rules function (PCRF) entity, a policy and charging enforcement function (PCEF) entity, an online charging system (OCS), and the like. The PCRF is mainly configured to determine a PCC rule for a user, and send the determined PCC rule to the policy and charging enforcement function (PCEF) entity. The PCEF is usually implemented based on a gateway and may be connected to a plurality of access networks.
Currently, a basic online charging mechanism is as follows: A charging trigger function (CTF) in a gateway completes quota application, quota management, and quota usage monitoring, performs a charging collection function, and detects, on the gateway, whether conditions for all trigger events/conditions (for example, a user location change or a quality of service (QoS) change) are met. A PCEF located in a gateway apparatus applies, by using rating group information, to an OCS for reservation of credit authorization, and reports, under a specific condition, collected service information to a charging system. The OCS deducts fees based on the reported service usage information.
In an existing network architecture, a data gateway (for example, a PDN Gateway (PGW)) is located in an excessively high position. To be specific, to cooperate in charging, cooperate with the PCRF, and the like, data gateways need to be centrally deployed at a relatively long distance from an access network, in other words, at a relatively long distance from a user. Consequently, each data packet has to be transmitted for an extremely long distance in a network before the data packet is forwarded for processing. In this case, 3GPP puts forward an idea that a control plane and a user plane (Control plane and User plane (CU), also referred to as a data plane) are separated. To be specific, data gateways are classified into a user plane and a control plane for separate deployment. Specifically, user plane gateways (UGW) may be deployed in a distributed manner, and may be moved downwards to a place at a relatively low position as compared with a conventional gateway (located in a relatively high position), for example, close to a Radio Access Network (RAN). Entity-to-entity (E2E) user plane transmission of some local services (whose server is a local server) may all be performed locally without passing through a backbone network, thereby reducing a lot of transmission delays. In addition, control plane gateways are still centrally deployed. The gateways herein may be PGWs in a fourth generation (4G) core network, or may be data gateways in a fifth generation (5G) core network.
In the prior art, in the architecture in which network control and data flow forwarding are separated, a charging enforcement function cannot be performed at one point. For example, because trigger conditions are distributed to a control plane entity and a user plane entity in a network, quota application, quota management, data flow information collection and the like cannot be performed at one point. Consequently, charging is performed at coordinated multi-points.
Therefore, in an existing charging mechanism and an existing charging solution, online credit control cannot be performed in the architecture in which network control and data flow forwarding are separated.